Apparatus for dispersing insecticides



March 16, 1943. w M SULLIVAN ET AL 2,313,976

APPARATUS FOR DISPERSING INSECTICIDES Filed Jan. 18, 1941 WILLIAM N.SULLIVAN 3 t LYLE D. GOQD nvenors Gttomeg Patented Mar. 16, 1943 APPARATUS FOR DISPERSING INSECTICIDES William N. Sullivan, Washington, D. (9., and Lyle D. Goodhue, Berwyn, Md., asslgnors to Claude R. Wickard, as Secretary of Agriculture of the United States of America, and to his successors Application January 18, 1941, Serial No. 375,048

2 Claims. (Cl. 261-) (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) reached that little or no settling occurs when the substance is suspended in air. By the use of the apparatus hereinafter described, it is possible to bring into use as iumigants substances which were hitherto useless because of their non-volatile nature. Many good insecticides previously had no use as fumigants until our new apparatus for dispersing them was developed.

A further object of our invention is to provide a small, light, and practical complete unit which can be easily and conveniently used for fumiga- I tion purposes.

Still another object of our invention is to provide an apparatus that will reduce possible decomposition of the insecticid during dispersing, and which will reduce, or practically eliminate, fire hazards accompanying such a method.

Our invention relates to a compactly designed, light in weight, new and useful mechanical device for the dispersion in air of non-volatile or practically non-volatile insecticides. It employs a new type of dispersing apparatus consisting of a specially constructed revolving cup which breaks up and distributes a solution of non-volatile insecticide over the inside surface of a heated cylinder where further dispersion is accomplished by instantaneous vaporization of the minute droplets. These minute explosions produce a suspension of the insecticide which is carried into the place to be fumlgated by a blast of air. The dispersed material resembles smoke or condensed vapor in appearance and'it belongs to the general class of colloids known as aerosols.

insecticide into a surface heated above the boiling point of the'solvent. Each droplet is exploded by the rapid production of vapor with the consequent dispersion of any non-volatile material in solution.

Our invention consists of a motor-driven perforated cup or similar device onto which the solution of insecticide is fed. The solution is can'ied by centrifugal force to the edge of the cup where it is thrown through an intervening air space against the inside of a. heated cylinder. The vapors and dispersed materials are conducted away by air from a. blower on the opposite end of the motor. The revolving disc is entirely enclosed and the air from the blower is conducted across the top of a cone-shaped lid in such a way that enough suction takes place to draw the dispersed material into the air stream. This method prevents the cooling effect of a current of air on the heated surface and conserves this heat energy for disintegration purposes.

Our invention is illustrated in the accompanying drawing, in which similar numerals refer to similar parts throughout the views.

By referring to the drawing, it will be seen that Fig. 1 is a cross-sectional view of the whole apparatug, while Fig. 2 is a top view of the perforated cup The apparatus comprises funnel I, the outlet of which is directly above the center of perforated cup 2, which revolves inside cylinder 3. This cylinder is heated, preferably by electricity with heating element 4, which is controlled by thermostat I, and covered with asbestos 6, or other insulating material. Revolving perforated cup 2 is attached to the shaft of electric motor I by any suitable means not shown." Heated cylinder 3 is attached, by any suitable means,

not shown, to disc 8 in which hole 9 is pro- Numerous types of Sprayers, blowers, and disintegrators have been described, but for the most part they are based on the simple process of spraying. Our disintegrator employs heat to obtain a much more complete dispersion of the particles after they receive a preliminary disintegration. This apparatus combines mechanical disintegration with dispersion, by means of heat in such a way that extremely effective aerosols of insecticides are formed. The dispersion of the nonvolatile material is accomplished by centrifugally throwing very small droplets of a solution of the vided for intake of air. Disc 8 is supported a convenient distance above the motor housin and may be attached thereto by bolts III, or other suitable means. Metal disc It, turned up near the center, is placed on top of disc 8, to act as a drip pan. The top of cylinder 3 is provided with cone shaped cover I 2, which intersects with tube l3, attached at an angle of with the axis of cone l2. Blower fan M, at the opposite end of electric motor I, has its outlet connected by tube It to asplrating nozzle [6 opening into tube l3 above the intersection with cone shaped lid l2. Tube I5 is adapted to function also as a handle. A top view of perforated cup 2 showing the arrangement of holes I! is given in Fig. 2. Any convenient number of holes can be used, but 10 are preferred. Five are arranged spirally over the walls of cup 2 beginning at the bottom and ending near the top 180 from the starting point. The other are arranged directly opposite over the other half of the circular wall. This arrangement provides for exact balance and excellent distribution of the material being sprayed. Holes I! are of such a. size that approximately the same amount of liquid escapes through each and still leave a small amount to be thrown over the top. The construction of perforated cup 2 is important in order that an even distribution of liquid will be made over the inside wall of heated cylinder 3. If all the liquid were deposited in one small area the dispersion obtained would be very inferior.

The foregoing is a description of the preferred type of our apparatus, but this same principle can be applied with other similar forms of apparatus. Electric power and heaters are preferred, but we do not limit ourselves to the use of electricity, since other sources of heat and power can be utilized.

In the operation of our apparatus the solution is fed into funnel l by suitable means, not shown, from where it is dropped onto perforated cup 2. The centrifugal force acting on the solution of insecticide throws it out through holes ll onto heated cylinder 3, which is held at a temperature from 300 to 500 C. where it is explosively disintegrated into colloidal dimensions. The dispersed insecticide is drawn out of the cylinder through cone-shaped lid l2 into tube I3 by the current of air from blower l4 escaping through aspirating nozzle IS. The dispersed material is thus ejected through tube [3 into the enclosure to be fumlgated.

In a practical use of our device we employed 5 cc. of safrole solution, containing 0.1 g. of rotenone and 5 cc. of safrole containing 0.1 g. of pyrethrum oleoresin, and dispersed it in a 200 cu. ft. chamber, in which 50 mushroom flies were liberated. All flies were dead after 24 hours. More practical tests have been run in an 18,000 cu. ft. mushroom house, which was infested with 2 species of mushroom flies. A control of over percent was obtained. Many other tests have been made with non-volatile materials or materials of very low volatility. A high initial concentration of the insecticide can be obtained. and in every case unusually high mortalities were obtained with such insects as the housefly, the cockroach, moths and beetles.

Having thus described our invention, what we claim for letters Patent is:

1. A dispersing apparatus comprising a cup rotatably mounted, said cup having a perforated circular wall, said wall sloping outwardly toward the top, the perforations of said wall being in a single row arranged spirally, a stationary housing about said cup, said housing having a circular wall facing said perforated wall, means for heating the wall of said housing, said housing having a cover, said cover having an outlet at the top thereof, suction means connected to said outlet, said housing having an air inlet below said cup, means for introducing a liquid into the cup, and means for rotating said cup.

2. A portable dispensing apparatus comprising a cup rotatably mounted, said cup having a perforated circular wall, a stationary housing about said cup, said housing having a circular wall facing said perforated wail, means for heating the wall of said housing, said housing having a cover, said cover having an outlet at the top thereof, means for introducing a liquid into said cup, 9. tube, said outlet being connected to said tube through the side thereof, a fan, a casing enclosing said fan, said casing having an outlet, a tapered tube coaxially disposed within said first-mentioned tube above said inlet, another pipe connecting the outlet of said fan casing with the larger end of said tapered tube, said connecting tube having a section comprising the handle of the apparatus, and means for rotating said cup and fan.

WIILIAM N. SULLIVAN. LYLE D. GOODHUE. 

